你好,
为你解答,
对于since的理解,你是正确的,它是多用于现在完成.但是它后面也可以跟句子,不一定就要跟时间点.
本题 It's almost three years since we met last time = It's been almost three years since we met las t time.
又如：It has been two years since he became a football player = He has been a football player since two years ago.
基本句型It is +一段时间＋since+一般过去时或现在完成时.
例如: It's twenty years since I've known her.我认识她已经二十年了.
How long is it since we last went to the theatre? 我们多久没去看戏了?
上面的知识点记住就行了.
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